Tube vibration control

For a while there, it seemed that many people used a vibration suppressor for tubes, and many manufacturers offered a version. Mapleshade had an elaborate all metal tube "jacket, complete with grounding wires that came off of it. More common were the rubber rings that would fit tightly over the tubes. I used to see them a lot - now, when I peruse members systems on this site and other sites, I do not see them as often. Did time teach us that they are not a necessary as we seemed to once think? Did we learn that they caused harm - concentrated heat, for example, and shortened tube life?

Just curious, as I have all-tube electronics, and wonder if I am neglecting something that would give them a little boost in performance.

Thanks, 

David